SUMMARY / ABSTRACT Placental maldevelopment and dysfunction characterize pregnancies complicated by conditions such as preeclampsia (PE). PE is a leading cause of maternal, fetal and neonatal mortality and morbidity and entails a heterogeneous etiology. Women who developed PE are at increased risk for long-term cardiovascular and metabolic disorders in later life. The lack of reliable methods for early diagnosis prior to clinical onset limits the opportunities for prevention and timely treatment of PE. We recently demonstrated excessive presence of aggregated proteins in the PE placenta. Our published work focused on transthyretin (TTR), the transporter of thyroxine and retinol. Most importantly, we showed that PE serum containing aggregated TTR when administered to pregnant mice could induce PE-like features. We detected elevated presence of aggregated TTR in the sera from women with PE. A novel method using ProteoStat, a rotor dye that only binds to aggregated proteins, has been developed. Our preliminary studies demonstrate that PE placenta displays heavy staining for both aggregated TTR and amyloid precursor protein (APP), suggesting mechanistic similarities to diseases such as Alzheimer's. Moreover, our preliminary data reveal that triggers that cause endoplasmic reticulum (ER) stress induce TTR and APP aggregation through impaired unfolded protein response (UPR) and autophagy-lysosome degradation machinery in human trophoblast cells. Here we propose to test the central hypothesis that persistent environmental stress leads to chronic endoplasmic reticulum (ER) stress, which exhausts the capacity of UPR and autophagy-lysosomal degradation machineries, resulting in the accumulation of misfolded and aggregated proteins. Aggregated proteins such as TTR and APP cause poor placentation and PE pathology. We further hypothesize that PE is a risk factor for the onset of AD like symptoms. We propose the following specific aims: 1) Using large sample size, adapt the protein aggregate detection assay as a predictive tool during early pregnancy, 2) Characterize the molecular events that contribute to the accumulation of protein aggregates in the cellular model of ER stress, and 3) Determine the generalizability of PE serum samples or aggregated proteins to cause PE-like features in our humanized mouse model. Evaluate mice with induced PE for the onset of AD-like features at 6-8 months age. The concept of protein aggregation in PE is novel and will provide a platform for comprehensive studies to pursue investigation into the multifactorial etiology of the disorder and the concepts for pathologies observed not only during pregnancy but also in later life.